Immunogenicity of SARS inactivated vaccine in BALB/c mice

• Published in: Immunology letters 2004-09, Vol.95 (2), p.139-143
• Main Authors: Xiong, Sheng, Wang, Yi-Fei, Zhang, Mei-Ying, Liu, Xin-Jian, Zhang, Chuan-Hai, Liu, Shi-Sheng, Qian, Chui-Wen, Li, Jiu-Xiang, Lu, Jia-Hai, Wan, Zhuo-Yue, Zheng, Huan-Yin, Yan, Xin-Ge, Meng, Min-Jie, Fan, Jiang-lin
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Viral - blood; Antibodies, Viral - immunology; Antibody Specificity; Antigens, Viral - immunology; IgG antibody; Immune Sera - immunology; Immunoglobulin G - blood; Immunoglobulin G - immunology; Inactivated vaccine; Kinetics; Mice; Mice, Inbred BALB C; Neutralization; Neutralization Tests; SARS; SARS coronavirus; SARS Virus - immunology; Severe Acute Respiratory Syndrome - immunology; Severe Acute Respiratory Syndrome - virology; Vaccines, Inactivated - immunology; Viral Vaccines - immunology
• ISSN: 0165-2478; 1879-0542
• DOI: 10.1016/j.imlet.2004.06.014

Severe acute respiratory syndrome (SARS) is a serious infectious threat to public health. To create a novel trial vaccine and evaluate its potency, we attempted to generate a SARS inactivated vaccine using SARS coronavirus (SARS-CoV) strain F69 treated with formaldehyde and mixed with Al(OH) 3. Three doses of the vaccine were used to challenge three groups of BALB/c mice. We found that the mice exhibited specific IgM on day 4 and IgG on day 8. The peak titers of IgG were at day 47 in low-dose group (1:19,200) and high-dose group (1:38,400) whereas in middle-dose group (1:19,200), the peak was at day 40. On day 63, the IgG levels reached a plateau. Neutralization assay demonstrated that the antisera could protect Vero-E6 cells from SARS-CoV's infection. Analysis of the antibody specificity revealed that the mouse antisera contained a mixture of antibodies specifically against the structure proteins of SARS-CoV. Furthermore, the mouse antisera conferred higher amount of antibodies against protein N, polypeptide S4 and S2 than those of proteins M and 3CL. These findings suggest that the inactivated SARS-CoV could preserve its antigenicity and the inactivated vaccine can stimulate mice to produce high levels of antibodies with neutralization activity. Results also suggest that polypeptides originating from protein N or S might be a potential target for the generation of a recombinant SARS vaccine.